1. Field of the Disclosure
The present disclosure relates to a vehicle seat.
2. Description of Related Art
Japanese Patent Application Publication No. 2010-052621 (JP 2010-052621 A) describes technology that includes a first airbag capable of inflating and deploying toward an occupant in a rear seat on a rear side of a backrest portion of a front seat, and a second airbag capable of inflating and deploying between the backrest portion of the front seat and an occupant in the front seat, and that supplies gas for inflating and deploying from a gas generating portion to both of the airbags separately. The second airbag is designed to have a longer internal pressure retention time than the first airbag.
However, typically, with a vehicle seat, an inclination angle of a seatback portion (backrest portion) of the seat and a position, such as a vehicle forward-rearward position, of the seat are able to be changed. The deployment region of a rear-seat airbag that is fixed to the vehicle seat changes with respect to an occupant seating space of a rear seat as the position of the vehicle seat changes. Therefore, the technology described in JP 2010-052621 A may not be able to effectively restrain a rear-seat occupant with the rear-seat airbag, depending on the position of the vehicle seat when the rear-seat airbag deploys.
As an example, a case will be described in which a rear-seat airbag 202 that is fixed to a seatback portion 200A of a vehicle seat 200 has deployed when the inclination angle of the seatback portion 200A (i.e., the angle of the seatback portion 200A with respect to the vehicle up and down direction) is equal to or greater than a predetermined angle, as shown in FIG. 19. In this case, the deployment region of the rear-seat airbag 202 with respect to a rear-seat occupant 206 seated in a rear seat 204 moves farther downward in the vehicle up and down direction than a proper position, so the head of the rear-seat occupant 206 will not be able to be effectively restrained.
Also, when the rear-seat airbag 202 that is fixed to the seatback portion 200A deploys and restrains the rear-seat occupant 206, a load toward the front of the vehicle is input to the seatback portion 200A, and the rear-seat airbag 202 receives reaction force from the seatback portion 200A. However, if the inclination angle of the seatback portion 200A is equal to or greater than a predetermined angle as shown in FIG. 19, the input angle of the load with respect to the back surface of the seatback portion 200A becomes smaller, so the rear-seat airbag 202 is unable to effectively obtain reaction force from the seatback portion 200A. As a result, the performance of restraining the head of the rear-seat occupant 206 is further reduced.